Mechanism for rotary engine

ABSTRACT

Mechanism useful in preparing the stator cavity of a rotary engine and in constraining the rotor of said engine to oscillatively revolve around a main shaft in conformity with said cavity comprises planetary pinions meshing with a spur gear and centered on said shaft, said pinions carrying a workplate on identically radially offset crank pins.

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[ MECHANISM FOR ROTARY ENGINE 3,260,135 7/1966 Eisenhardt.................,...... 74/304 x [76] Inventor: Leonard R. Nester, 2139 Magnolia Avenue E" s p Mirm Primary Examiner-Charles J. Myhre Assistant Examiner-F. D. Shoemaker Flledl 30, 1971 Attorney-Gilbert B. Gehrenbeck {21] Appl. No.: 203,211

[57] ABSTRACT {52] {15. Cl 418/61, 74/804, 8.2/1.3 Mechanism useful in p p ng th stat r ca ity of a r0- {51] Int. Cl. F011: 1/02 y engine and in constraining th r t r f said ngine [58] Field of Search 74/804, 802, 86; to oscillatively r v l nd a main shaft in confor- 418]54 61; 32/13 19 1,3 mity with said cavity comprises planetary pinions meshing with a spur gear and centered on said shaft, said [56] References Cited pinions carrying a workplate on identically radially off- UNITED STATES PATENTS set crank 3,2l6,405 11/1965 Jungbluth 74/804 8 Claims, 113 Drawing Figures Patented July 10, 1973 3,744,941

3 SheetsSneet 1 B4 m I66 01 Paterited July 10, 1973 f 3,744,941

3 Sheets-Sneet Li MECHANISM FOR ROTARY ENGINE This invention relates to rotary engines and in particular to supporting and constraining mechanism useful in both the construction and the operation thereof.

One well-known form of rotary engine is described in Wankel et al U.S. Pat. No. 2,988,065, the disclosures of which are included here by reference. In a preferred form the Wankel engine employs a triangular rotor which oscillatively revolves within a two-lobed epitrochoidal cavity in a stator equipped with spark plug, inlet port and outlet port. The engine is connected to appropriate ignition mechanism, carburetor or other source of fuel, exhause manifold, and other auxiliary equipment as needed. The engine operates in typical four-cycle mode, the sequence of intake, compression, expansion and exhaust occurring for each of the three chambers defined by the triangular rotor within the epitrochoidal cavity during each complete revolution of the rotor.

The present invention provides novel mechanism useful both in supporting and constraining the rotor in the finished engine and also in the initial machining and polishing of the curved peripheral stator surface. Close control of rotor movement is accomplished, thereby permitting improved sealing of the engine chambers. Limitations on shaft diameters and other dimensions are relaxed, and other advantages are obtained as will be made apparent in connection with the ensuing description.

In general, the mechanism of the invention comprises the following components having the indicated functions. A main or drive shaft serves for input or output of power. It is supported by at least one main frame member, which may be a wall or walls of a stator or a component of a milling machine. Attached to the shaft for rotation therewith is a support plate carrying a plurality of equally angularly and radially spaced support shafts with pinion gears or pairs of gears mounted thereon. The pinions mesh with a central spur gear, which in the preferred mechanism has twice the effective diameter of the pinions, and which is affixed to the frame member, the main shaft rotating axially of the spur gear. Offset pins or equivalent crank members carried by the pinions support a workplate which in an engine or pump serves as a side plate of the rotor and in a milling machine serves as a base plate for a toolholder. By this means, rotation of the main shaft is accompanied by oscillative rotation of the workplate such that the latter describes a generally epitrochoidal outline. When a cutting or polishing tool is suitably affixed to the workplate, the device is therefore capable of machining the interior peripheral wall of an appropriate casting to the exact shape which will subsequently be followed by a rotor comprising an equivalent mechanism and workplate.

In the accompanying drawing,

FIG. 1 is a sectional end elevation approximately at line 1-1 of FIG. 2, and FIG. 2 is a sectional side elevation approximately at line 22 of FIG. 1, of one exemplary form of mechanism incorporated in a rotary engme,

FIG. 3 is a sectional side elevation taken approximately at line 3-3 of FIG. 4, and FIGS. 4 and 5 are partial plan views taken approximately at lines 4-4 and 5-5 respectively of FIG. 3, of another form of mechanism also incorporated in an engine,

FIG. 6 is a plan view of a rotor apex seal,

FIG. 7 is an elevational view in partial section of the seal of FIG. 6,

FIG. 8 is an elevational view in full section of the apex seal taken approximately at line 8-8 of FIG. 6,

FIG. 9 is a transverse elevational sectional view taken approximately at line 99 of FIG. 6,

FIG. I0 is a transverse sectional view, taken approximately at line l0-ll0 of FIG. ll, of a rotor edge seal,

FIG. I1 is a sectional side elevation, taken approximately at line Ill-II of FIG. 12, of a simplified form of mechanism, being in this instance incorporated in a milling machine,

FIG. 12 is a partial end elevation of the device of FIG. ll with portions broken away to show detail, and

FIG. 13 is a detail view of a tool holder component.

The engine 12 of FIGS. 1 and 2 comprises a stator or casing 14 enclosing a generally triangular hollow rotor 16 supported on a central shaft 18. The stator cavity 17 is defined by a generally epitrochoidal curved wall 20 between opposing spaced planar side walls 22, 23. A base 24 serves as a mounting support for the engine. A threaded opening 25 in the wall 20 receives a spark plug, and threaded intake opening 26 and exhaust opening 23 afford connection to fuel source and exhaust manifold respectively.

Spur gears 30, 32 are supported within the rotor cavity on tubular axial extensions 34, 36 of the side walls 22, 23 of the stator. Suitable bushings, not shown, facilitate rotation of the shaft within the tubes.

The rotor 16 is supported on the shaft by mechanism indicated generally at 37 and consisting of a triangular plate 38 keyed at its center to the shaft 18 and carrying at each apex a short shaft parallel to the main shaft and axially supporting at its ends a pair of pinions which mesh with the spur gears mounted on the stator and which in turn support the rotor on outwardly extending radially offset crank pins. Thus, shaft 40 carries pinions 46 and 48 which support the rotor side walls 64 and Til on crank pins 58 and 66; shaft 42 carries pinions 50 (not shown) and 52 with pins (not shown) and 67; and shaft 44 carries pinions 54 and S6 with pins 62 and 68. Suitable bushings, not shown, are again provided where necessary to serve as bearing surfaces.

Openings 72, 74 in the rotor side walls 64, '70 permit oscillation of the rotor about the tubular supports 34, 36 as the rotor is driven around the interior of the stator chamber during operation of the engine. The rotor is constrained to follow the peripheral outline of the stator chamber by the action of the supporting mechanism, which causes one full turn of the shaft for each full circuit by the rotor.

Fastening means for joining the two halves of the stator are indicated in FIG. 2 as bolts 29 and it will be understood that equivalent means for securing various other components are likewise to be included but are omitted here for clarity of illustration. For example, the rotor walls 64 and will normally be joined to the triangular peripheral wall 71 by screw and gasket means. It will be further understood that various modifications of rotor and stator, e.g., as shown in the Wankel et al. patent, are here contemplated. As but one example, the portions of the rotor periphery between the apexes may be depressed to provide a connecting channel between lobes of the stator cavity during rotation.

The engine 112 of FIGS. 3-5 contains two triangular rotors 115a and 1161; within separate chambers 117a and 11712 disposed at opposite ends of a radially enlarged central chamber 117c in the stator housing 114. The housing supports axial extension tubes 134, 136 to which are affixed spur gears 130, 132. The main shaft 118 supports a triangular plate 138 keyed thereto and which carries three short shafts each supporting two pinions. Thus, pinions 146 and 148 are carried by shaft 140; pinions 150 (not shown) and 152, by shaft 142; and pinions 154 and 156 by shaft 144. Correspondingly radially offset outwardly extending crank pins 158, 160 (not shown) and 162 from pinions 146, 150 and 154 respectively support extended side wall 164 of rotor 116a, while pins 166, 167 and 168 from pinions 148, 152 and 156 respectively support extended side wall 170 of rotor 116b. Extended side walls 164 and 170 serve as inner side walls of the two stator chambers 117a and 1l7b and carry edge seals 178 which bear against the side wall surfaces of chamber ll7c. Peripheral wall 169 joins the two side walls 164, 170. Peripheral walls 120a, 120b join outer side walls 122, 123 to the extended inner section. Propulsion forces produced during the expansion cycles in the stator chambers 117a and 117b and acting upon the rotors 116a and 116b are transmitted through the justdescribed mechanism 137 therebetween to the shaft 118.

Enclosure of the constraining assembly 37 within the rotor as in FIGS. 1 and 2 permits a compact structure but limits the extent of rotor oscillation and the compression ratio available in the engine. The external constraint system used in the engine of FIGS. 3-5 is somewhat less compact but permits much increased oscillation of the rotor. In the latter engine the crank pins 158, 160 and 162 are in line with the apexes of the rotor 116a and correspondingly the pins 166, 167 and 168 are in line with the apexes of the rotor 116b. As a result, the peripheral wall of each stator chamber is, or closely approximates, a curtate epicycloid. The term epitrochoid is considered to encompass this and other closely allied curve forms as described by the apexes of the rotors supported as herein described.

Compression is maintained within the engine cavities by means of seals at the apex and side edges of the rotor. The apex seals 76, illustrated in FIGS. 6-9, com prise a central cross-shaped member 80 and four triangularly cross-sectioned segments 82, 84, 86 and 88 fitting thereagainst, all within an apex channel 89 as in FIG. 9. The four arms of the cross are generally triangular in cross-section and the long arms terminate in a reverse slant step conforming to the inner slant step face of the edge seal strips 90, 92 as illustrated in FIGS. 7, 8 and 10. The cross has an inner central cavity 94 in line with a corresponding cavity 96 in the rotor shell 16 and within which a coil spring 98 is held under compression.

Edge seals 78 as shown in FIG. 10 include an outer strip 90 disposed within a channel 100 extending along the side margin of the rotor side plate and rest against an inner strip 102 which is urged outwardly by means of springs 104 arranged along the channel at suitable intervals. The matching slant faces of the two strips urge the strips against the side walls of the cavity, and the outer face of the outer strip 90 is urged against the surface of the stator wall. Somewhat analogously, the slant face of the outer strip contacts the slant face at the end of the cross member 80 to urge both members into contact with the stator surface; and the slant faces of the four arms of the member 80 press the segments 82, 84, 86 and 88 against the side walls of the apex channel 89 while the outer surfaces of the cross contact the stator surface 20.

Since thesole force urging the several apex seals members against the stator surfaces, other than centrifugal force on the seal members themselves, is that provided by the compression springs'98, it is possible to obtain effective sealing with a minimum of frictional wear on seal members and stator surfaces.

FIGS. 11-13 illustrate a modified form of mechanism which may likewise be incorporated in a rotary engine but is here shown in a milling machine. A frame member 222 supports a single spur gear 230, held thereto by screws 231. A main drive shaft 218 rotatably disposed axially of the spur gear is keyed to a circular support plate 238 which supports shafts 240, 242 (not shown) and 244. Pinions 254 and 256 are keyed to shaft 244 which rotates in a suitable bushing within plate 238. A radially offset outwardly extending crank pin 268 in pinion 256 supports a workplate 264. Similarly, pinions 250 (not shown) and 246 mesh with spur gear 230, are keyed to shafts 242 and 240 which are keyed to pinions 252 and 248 from which crank pins 267 and 266 extend into and support workplate 264.

The pinions 240, 252 and 256 in this instance serve only as crank lever arms and, together with their associated short shafts and extended pins, may be replaced by one-piece crank members; but the structure illustrated is convenient to construct and assemble and is presently preferred.

An adjustable toolpiece 279 consisting of a body 280, cap 282, scale 286, washer 288, bolt 284, and three equiangularly disposed toolholders 290 (of which but one is seen in section in FIG. 11) is fastened to workplate 264. The three toolholders slide within radial channels 293 along the face of the body 280 and are provided with segmental threades 291 meshing with continuous threads 283 on the inner surface of the cap 282. Rotation of the cap about the central supporting bolt 284 to a desired degree as indicated on the scale 286 provides for radial adjustment of the toolholders. Cutting or polishing tools 292, held within the toolholders 290 by screws 294 as indicated in FIG. 13, may thereby be adjusted to any desired radius. Rotation of the shaft 218 while feeding the toolpiece into and out of the cavity of a blank or casting which is to be machined, and with periodic adjustment of the toolholders, permits the machining of a stator chamber which precisely conforms to the movement of a rotor of appropriate dimensions when supported on an identically dimensioned mechanism.

What is claimed is as follows:

1. A mechanism comprising a main shaft, a main frame member supporting said main shaft for rotation, a spur gear centered about said main shaft and affixed to said main frame member, a support plate affixed to said main shaft for rotation therewith and adjoining said spur gear, a plurality of equally angularly spaced pinions each axially mounted on a short shaft carried by said support plate and in mesh with said spur gear for rotation therearound, and operatively affixed to each said pinion a radially offset crank pin parallel to said short shaft, and a workplate supported on said crank pins.

2. Mechanism of claim 1 wherein the diameter of said spur gear is twice that of said pinions.

3. Mechanism of claim 2 wherein said workplate is between said main frame member and said spur gear. cm 4. Mechanism of claim 2 wherein said spur gear and said workplate are on opposite sides of said support plate.

5. Mechanism of claim 2 wherein said main frame member is a side plate of a stator of a rotary engine and said workplate is a side plate of a rotor oscillatively rotatable therein.

6. Mechanism of claim 5 wherein are included, disposed at opposite sides of said support plate, two stator side plates, two spur gears, and two sets of each three carries a radially adjustable cutting mechanism.

a: s s 

1. A mechanism comprising a main shaft, a main frame member supporting said main shaft for rotation, a spur gear centered about said main shaft and affixed to said main frame member, a support plate affixed to said main shaft for rotation therewith and adjoining said spur gear, a plurality of equally angularly spaced pinions each axially mounted on a short shaft carried by said support plate and in mesh with said spur gear for rotation therearound, and operatively affixed to each said pinion a radially offset crank pin parallel to said short shaft, and a workplate supported on said crank pins.
 2. Mechanism of claim 1 wherein the diameter of said spur gear is twice that of said pinions.
 3. Mechanism of claim 2 wherein said workplate is between said main frame member and said spur gear.
 4. Mechanism of claim 2 wherein said spur gear and said workplate are on opposite sides of said support plate.
 5. Mechanism of claim 2 wherein said main frame member is a side plate of a stator of a rotary engine and said workplate is a side plate of a rotor oscillatively rotatable therein.
 6. Mechanism of claim 5 wherein are included, disposed at opposite sides of said support plate, two stator side plates, two spur gears, and two sets of each three pinions, and wherein said rotor is generally triangular in cross-section and oscillates within a generally epitrochoidal stator cavity.
 7. Mechanism of claim 5 wherein said rotor includes outwardly spring-biased sealing members at each apex and along each side margin, each said sealing member including a base having at least one slant side surface and at least one sealing element lying alongside said base and having a mating slant surface.
 8. Mechanism of claim 1 wherein said workplate carries a radially adjustable cutting mechanism. 